Sex differences in Ngn3 expression in primary hypothalamic neurons is determined by sex chromosomes

CISTERNAS, C.D.; TOMÉ, K; SCERBO, M.J.; CAMBIASSO, M.J.

Huerta Grande - Córdoba

Congreso; XXVIII Reunión Anual de la Sociedad Argentina de Investigación en Neurociencias (SAN); 2013

Sociedad Argentina de Investigación en Neurociencias (SAN)

Brain phenotype is determined by the hormonal profile generated by the gonads during the critical period of development (E18-PN10). Over the years it has been accumulated evidence showing the existence of sex differences before this critical period. Previous works have demonstrated that male hypothalamic neurons, which show a retarded neuritic differentiation compared to female neurons, showed also decreased mRNA levels of the neuritogenic factor Ngn3. In order to study if cell autonomous actions of sex chromosomes are involved in the generation of sex differences in the brain we evaluated Ngn3 mRNA in neuronal cultures of transgenic mice which combine a deletion of the Sry gene from the Y chromosome with its reinsertion into an autosome. This model comprises XX and XY gonadal males (XXM and XYM) and XX and XY gonadal females (XXF and XYF). Neuronal hypothalamic cultures of E14 embryos were performed segregated by sex and genotype. After 72h in vitro RNA were extracted and cDNA obtained by reverse transcription. The mRNA transcript levels of Ngn3 were measured by qRT-PCR. Neurons carrying XY chromosomes (XYM and XYF) showed lower expression levels of Ngn3 than those carrying XX (XXM and XXF; p